Molecular dynamics simulations of the Ba+ ion mobility in liquid xenon

Abstract

Abstract Improved molecular dynamics approach is proposed to simulate the mobility of atomic ion in the non-polar solvents such as liquefied rare gases. The many-body solvent polarization is described in the dipole approximation as the Car-Parrinello degrees of freedom of the Nosé-Poincaré-Anderson extended Hamiltonian function for NPT ensemble. Separation of the dipole induction from other ion-neutral interaction terms retained in the force field is accomplished by reparameterizing the accurate ab initio potential energies for di- and tri-atomic fragments. Effect of the external electric field is treated perturbatively, by reconstructing the trajectories at a finite external field from those propagated in the field-free case. Mobility definitions that use ensemble averages of ion velocity and field-induced dragging force are analyzed together with their Green-Kubo counterparts. The simulations of the Ba+ mobility in liquid Xe are in good agreement with the experimental data [Jeng S-C et al. 2020 J. Phys. D 42 035302].